Effect of Secondary Boiling on PCCS Condensation

An experimental and theoretical study is performed for the steam condensation in a vertical tube bundle passive condenser scaled for the PCCS condenser in the ESBWR. The comparison of tube bundle experimental data with the single tube data by both the experiments and models shows that the single tube secondary HTC is between 25% - 35% less than what was recorded for the tube bundle, and the tube bundle condensation rates are slightly higher than the data from the single tube test sections due to turbulent mixing effect which increases the condensation heat removal. This increase in secondary HTC thus results in higher condensate mass flow rates. Tube bundle boundary layer model and heat and mass analogy model were then developed for the prediction of the film wise steam condensation with non-condensable gas in a vertical tube bundle. The predictions from the models are compared with the experimental data for various complete condensation and through flow conditions and the agreement is satisfactory. The LOCA parameters predicted by the boundary layer model and heat and mass analogy model with tube bundle pool boiling are presented.